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-rw-r--r--absl/memory/memory.h33
-rw-r--r--absl/memory/memory_exception_safety_test.cc18
-rw-r--r--absl/memory/memory_test.cc43
3 files changed, 92 insertions, 2 deletions
diff --git a/absl/memory/memory.h b/absl/memory/memory.h
index cd818cff..c43e1566 100644
--- a/absl/memory/memory.h
+++ b/absl/memory/memory.h
@@ -636,6 +636,39 @@ struct default_allocator_is_nothrow : std::true_type {};
struct default_allocator_is_nothrow : std::false_type {};
#endif
+namespace memory_internal {
+// TODO(b110200014): Implement proper backports
+template <typename ForwardIt>
+void DefaultConstruct(ForwardIt it) {
+ using value_type = typename std::iterator_traits<ForwardIt>::value_type;
+ ::new (static_cast<void*>(std::addressof(*it))) value_type;
+} // namespace memory_internal
+
+#ifdef ABSL_HAVE_EXCEPTIONS
+template <typename ForwardIt, typename Size>
+void uninitialized_default_construct_n(ForwardIt first, Size size) {
+ for (ForwardIt cur = first; size > 0; static_cast<void>(++cur), --size) {
+ try {
+ absl::memory_internal::DefaultConstruct(cur);
+ } catch (...) {
+ using value_type = typename std::iterator_traits<ForwardIt>::value_type;
+ for (; first != cur; ++first) {
+ first->~value_type();
+ }
+ throw;
+ }
+ }
+}
+#else // ABSL_HAVE_EXCEPTIONS
+template <typename ForwardIt, typename Size>
+void uninitialized_default_construct_n(ForwardIt first, Size size) {
+ for (; size > 0; static_cast<void>(++first), --size) {
+ absl::memory_internal::DefaultConstruct(first);
+ }
+}
+#endif // ABSL_HAVE_EXCEPTIONS
+} // namespace memory_internal
+
} // namespace absl
#endif // ABSL_MEMORY_MEMORY_H_
diff --git a/absl/memory/memory_exception_safety_test.cc b/absl/memory/memory_exception_safety_test.cc
index 55e8f36f..fb8b561d 100644
--- a/absl/memory/memory_exception_safety_test.cc
+++ b/absl/memory/memory_exception_safety_test.cc
@@ -20,11 +20,14 @@
namespace absl {
namespace {
-using Thrower = ::testing::ThrowingValue<>;
+constexpr int kLength = 50;
+using Thrower = testing::ThrowingValue<testing::TypeSpec::kEverythingThrows>;
+using ThrowerStorage =
+ absl::aligned_storage_t<sizeof(Thrower), alignof(Thrower)>;
+using ThrowerList = std::array<ThrowerStorage, kLength>;
TEST(MakeUnique, CheckForLeaks) {
constexpr int kValue = 321;
- constexpr size_t kLength = 10;
auto tester = testing::MakeExceptionSafetyTester()
.WithInitialValue(Thrower(kValue))
// Ensures make_unique does not modify the input. The real
@@ -45,5 +48,16 @@ TEST(MakeUnique, CheckForLeaks) {
}));
}
+TEST(MemoryInternal, UninitDefaultConstructNNonTrivial) {
+ EXPECT_TRUE(testing::MakeExceptionSafetyTester()
+ .WithInitialValue(ThrowerList{})
+ .WithOperation([&](ThrowerList* list_ptr) {
+ absl::memory_internal::uninitialized_default_construct_n(
+ list_ptr->data(), kLength);
+ })
+ .WithInvariants([&](...) { return true; })
+ .Test());
+}
+
} // namespace
} // namespace absl
diff --git a/absl/memory/memory_test.cc b/absl/memory/memory_test.cc
index dee9b486..8ff1945d 100644
--- a/absl/memory/memory_test.cc
+++ b/absl/memory/memory_test.cc
@@ -611,4 +611,47 @@ TEST(AllocatorNoThrowTest, CustomAllocator) {
EXPECT_FALSE(absl::allocator_is_nothrow<UnspecifiedAllocator>::value);
}
+TEST(MemoryInternal, UninitDefaultConstructNTrivial) {
+ constexpr int kInitialValue = 123;
+ constexpr int kExpectedValue = kInitialValue; // Expect no-op behavior
+ constexpr int len = 5;
+
+ struct TestObj {
+ int val;
+ };
+ static_assert(absl::is_trivially_default_constructible<TestObj>::value, "");
+ static_assert(absl::is_trivially_destructible<TestObj>::value, "");
+
+ TestObj objs[len];
+ for (auto& obj : objs) {
+ obj.val = kInitialValue;
+ }
+
+ absl::memory_internal::uninitialized_default_construct_n(objs, len);
+ for (auto& obj : objs) {
+ EXPECT_EQ(obj.val, kExpectedValue);
+ }
+}
+
+TEST(MemoryInternal, UninitDefaultConstructNNonTrivial) {
+ constexpr int kInitialValue = 123;
+ constexpr int kExpectedValue = 0; // Expect value-construction behavior
+ constexpr int len = 5;
+
+ struct TestObj {
+ int val{kExpectedValue};
+ };
+ static_assert(absl::is_trivially_destructible<TestObj>::value, "");
+
+ TestObj objs[len];
+ for (auto& obj : objs) {
+ obj.val = kInitialValue;
+ }
+
+ absl::memory_internal::uninitialized_default_construct_n(objs, len);
+ for (auto& obj : objs) {
+ EXPECT_EQ(obj.val, kExpectedValue);
+ }
+}
+
} // namespace